package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;

    /**
     * 关注或取关
     * @param followUserId
     * @param isFollow
     * @return
     */
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //0.获取用户id
        Long userId = UserHolder.getUser().getId();

        String key = "follows:" + userId;

        //1.判断isFollow是关注还是取关
        if(isFollow){
            //2.关注，新增数据
            Follow follow = new Follow();
            follow.setFollowUserId(followUserId);
            follow.setUserId(userId);

            boolean isSuccess = save(follow);
            if(isSuccess == true){
                //成功保存至数据库，同时将关注用户添加至当前用户redis集合中
                stringRedisTemplate.opsForSet().add(key, followUserId.toString());
            }

        }else {
            //3.取关，删除数据 delete from .. where ..=.. and ..=..
            boolean isSuccess = remove(new QueryWrapper<Follow>()
                    .eq("user_id", userId)
                    .eq("follow_user_id", followUserId));

            if(isSuccess == true){
                //从redis集合移除
                stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
            }

        }

        return Result.ok();
    }

    @Override
    public Result isFollow(Long followUserId) {
        //0.获取用户id
        Long userId = UserHolder.getUser().getId();

        //1.查询是否关注 select * from .. where .......
        Integer count = query().eq("user_id", userId).eq("follow_user_id", followUserId).count();

        //2.count>0 说明关注
        return Result.ok(count > 0);
    }

    /**
     * 共同关注
     * @param id
     * @return
     */
    @Override
    public Result followCommons(Long id) {
        //1.获取当前登录用户
        Long userId = UserHolder.getUser().getId();
        String keyU =  "follows:" + userId;
        String keyF = "follows:" + id;

        //2.求用户共同关注
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(keyF, keyU);

        if(intersect == null || intersect.isEmpty())
            return Result.ok(Collections.emptyList());

        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());

        //3.利用id查询用户列表
        List<UserDTO> userDTOS = userService.listByIds(ids)
                .stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());

        return Result.ok(userDTOS);
    }
}
